Broken Rail Detection System

ABSTRACT

A system is for performing broken rail detection on a railway track. The system includes at least one locomotive and a monitoring entity. Each locomotive includes a receiver for receiving a track signal that is circulating in the railway track and a processing unit that is in communication with the receiver. The processing unit is operative for detecting a characteristic of the track signal and generating a signal indicative of a potential broken rail in response to a change in the characteristic of the track signal. The locomotive further includes a wireless transmitter for transmitting the signal indicative of a potential broken rail over a wireless communication link. The monitoring entity includes a receiver for receiving the signal indicative of a potential broken rail and a processing unit for detecting a broken rail at least in part on the basis of the signal indicative of a potential broken rail from the locomotive.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/635,003, filed on Dec. 13, 2004, which is expressly incorporated herein in its entirety by reference thereto.

FIELD OF THE INVENTION

The present invention relates to the field broken rail detection systems, and more particularly to detection systems that use voltage and/or current signals circulating in the railway track for detecting broken rails.

BACKGROUND INFORMATION

In order to ensure the safety of railway transportation, it is not only important to keep the locomotives in good working condition, it is also important to keep the railway tracks themselves in good working condition. Due to excessive use, and environmental conditions such as extreme temperatures, railway tracks can deteriorate and eventually break. It is therefore important to monitor the condition of the railway tracks in order to ensure that they do not include breaks that could cause them to be unsafe.

Certain systems for detecting broken rails are conventional. As shown in FIG. 1, such systems generally include wayside-based equipment 10 that is positioned in proximity to the railway tracks 12. The wayside-based equipment 10 is in communication with a transmitter 14 and a receiver 16. The railway track 12 that is being monitored is divided into sections by placing shunts 18 across the rails. By so doing, the railway track 12 and the shunts 18 create a closed conductive loop. The transmitter 14 then introduces either a current or a voltage signal into the closed loop, such that the signal is able to circulate through the railway track 12. Meanwhile, the receiver 16 monitors this signal circulating through the closed loop of the railway track 12. When a break occurs in the railway track 12, the break will interrupt the path of the signal, thus preventing the signal from reaching the receiver 16. When the wayside equipment 10 detects the absence of the signal at the receiver 16, the wayside-based equipment 10 determines that there is a break in the railway tracks 12.

Unfortunately, such broken rail detection systems are plagued with numerous deficiencies. A first such deficiency is that a significant amount of wire is required in order to connect the transmitters 14 and the receivers 16 to the wayside equipment 10. This is not only costly, but is also difficult to maintain.

A further deficiency with existing systems is that when trains are running on the track, the broken rail detection system cannot always be used. More specifically, when a train is travelling on the railway track between the transmitter 14 and the receiver 16, the train's axles act as shunts. As such, if a train is on the track, it will short out the section of track between itself and the shunt. Referring to FIG. 1, and assuming that a train's axles are positioned just in front of the break in the rails 12, the train's axles will complete the closed loop, such that the receiver 16 will continue to receive the signal that is circulating in the rails, regardless of the fact that there is a break in the rails just beyond the train's axle. Therefore, depending on the placement of the transceiver 14 and the receiver 16, the portion of the rails positioned beyond the portion of the track that is shunted by the train cannot be monitored. As such, the wayside equipment will not be able to accurately perform broken rail detection on the rails when there are trains travelling thereon. The more trains that are running on the track, the less the system can accurately perform broken rail detection, since the trains cause shunting of so much of the track.

In light of the above, it can be seen that there is a need in the industry for an improved broken rail detection system that alleviates, at least in part, the deficiencies of the prior art, and improves on the overall efficiency of the systems.

SUMMARY

In accordance with a first broad aspect, example embodiments of the present invention provide a locomotive for travelling on a railway track. The locomotive includes a receiver for receiving a track signal that is circulating in the railway track and a processing unit that is in communication with the receiver. The processing unit is operative for detecting a characteristic of the track signal and for generating a signal indicative of a potential broken rail in response to the characteristic of the track signal circulating in the railway track.

The locomotive may further include a transmitter for transmitting the track signal into the railway track. It should be appreciated that the track signal can also be introduced into the railway track by a different locomotive, or by track-side equipment.

In accordance with an example embodiment of the present invention, a system is provided for performing broken rail detection on a railway track. The system includes at least one locomotive and a monitoring entity. The locomotive includes a receiver for receiving a track signal that is circulating in the railway track and a processing unit that is in communication with the receiver. The processing unit is operative for detecting the presence of the track signal and generating a signal indicative of a potential broken rail in response to the absence of the track signal circulating in the railway track. The locomotive further includes a wireless transmitter for transmitting the signal indicative of a potential broken rail over a wireless communication link. The monitoring entity includes a receiver for receiving the signal indicative of a potential broken rail and a processing unit for detecting a broken rail at least in part on the basis of the signal indicative of a potential broken rail from the locomotive.

In accordance with an example embodiment of the present invention, a monitoring entity is provided for performing broken rail detection. The monitoring entity includes a wireless receiver and a processing unit. The wireless receiver is operative for receiving a signal from at least one locomotive; the signal being indicative of a potential broken rail. The processing unit is operative for detecting a broken rail at least in part on the basis of the signal from the at least one locomotive.

In accordance with an example embodiment of the present invention, a system is provided for performing broken rail detection. The system includes a receiving device for mounting onboard a locomotive that is travelling on a railway track. The receiving device is operative for receiving a track signal that is circulating in the railway track. The system further includes a processing device in communication with the receiving device. The processing device is operative for detecting the presence of the track signal and generating a signal indicative of a potential broken rail in response to the absence of the track signal circulating in the railway track.

These and other aspects and features of example embodiments of the present invention are described in further detail in the following description with reference to the appended Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a conventional broken rail detection system.

FIG. 2 shows a top schematic view of a locomotive-based broken rail detection system in accordance with a non-limiting example embodiment of the present invention.

FIG. 3 shows a schematic diagram of a locomotive in accordance with a non-limiting example embodiment of the present invention, travelling over a portion of railway track.

FIG. 4 shows a non-limiting schematic diagram of portions of a railway track surveyed by the locomotive-based broken rail detection system of FIG. 2.

FIG. 5 shows a block diagram of a locomotive in accordance with a non-limiting example embodiment of the present invention.

FIG. 6 shows a schematic diagram of a non-limiting example embodiment of the present invention.

FIG. 7 shows a non-limiting example of a flow diagram performed by a locomotive for generating a signal indicative of a potential broken rail in accordance with a non-limiting example embodiment of the present invention.

DETAILED DESCRIPTION

Shown in FIG. 2 is a broken rail detection system 20 in accordance with a non-limiting example embodiment of the present invention. The broken rail detection system 20 includes a monitoring entity 22 that is in communication with one or more locomotives 24. For the purposes of the following description, three locomotives 24 a, 24 b and 24 c are included in the schematic diagram of FIG. 2. It should, however, be understood that any number of locomotives 24 can be included as part of the broken rail detection system 20, without departing from the spirit of the present invention.

The monitoring entity 22 is responsible for monitoring the condition of the railway track 24 in a predefined area or region in order to determine, among other things, whether the rails in that region include a break. The predefined area or region may be based on a certain length of railway track (i.e., 100 miles of track, for example) or based on a certain geographical area.

The monitoring entity 22 can be a track-side device, such as wayside equipment, or can be a remotely located device, such as a computing unit that is located at a control station, for example. In use, monitoring entity 22 is operative for detecting a broken rail in the railway track 26 at least in part on the basis of signals received from the locomotives 24 travelling on the railway track 26. As the locomotives 24 a, 24 b and 24 c travel along the railway track 26, they are operative for surveying a portion of the railway track 26 in order to detect a potential break in the rails. The surveying is performed by monitoring a track signal that is circulating in the railway track 26. As will be described in more detail below, the track signal can be introduced into the railway track 26 by the locomotive that is monitoring the signal, by a different locomotive or by track-side equipment.

Upon detection of a potentially broken rail in the portion of railway track being surveyed, the locomotive transmits a signal indicative of a potential broken rail to the monitoring entity 22. As such, the monitoring entity 22 includes a receiver 21 for receiving the signals from the locomotives 24 a, 24 b and 24 c, and a processing unit 23 for determining, among other things, if there is a break in one of the rails. As will be described in more detail below, the monitoring entity 22 can perform the broken rail detection solely on the basis of the signals received from the locomotives 24, or in combination with conventional techniques (as described above) which involve introducing a signal into the rails via a track-side transmitter 25.

In order to facilitate the ability of locomotives 24 a, 24 b and 24 c to survey portions of the railway track 26, the railway track 26 is divided into sections via shunts 28. The railway track 26 shown in FIG. 2 includes five shunts, which have been labelled 28 a, 28 b, 28 c, 28 d and 28 e for clarity.

In accordance with a non-limiting example embodiment, at least some of the locomotives 24 a, 24 b and 24 c are operative for introducing a signal into the track 26. Shown in FIG. 3 is a non-limiting example embodiment of a locomotive 24 in accordance with the present invention. As shown, the locomotive 24 includes a transmitter 30 for issuing a signal into a rail of the railway track 26, and a receiver 32 for receiving the signal introduced into the railway track 26. The transmitter 30 and the receiver 32 are positioned on the locomotive 24 such that they are set correctly with respect to the rails.

The signal that is transmitted into the rails can either be a current signal or a voltage signal. In a non-limiting example embodiment, the signal can be, but is not limited to, a low frequency audio signal having a frequency in the range of 4,000 Hz to 10,000 Hz. Such signals are inductively transmitted into the rails.

Once the signal has been introduced into one of the rails by the transmitter 30, the signal travels through the rail to the nearest shunt 28 and then travels back towards the locomotive 24 through the other rail. The shunt 28 can be a conductive rod that is placed across the rails of the track 26, or alternatively, the shunt 28 can be an axle of another locomotive travelling on the track 26. Once the signal has traveled through the shunt 28, it travels back towards the locomotive 24 that issued the signal. That locomotive's axle 34 then acts as a second shunt, such that a closed loop is created between the locomotive 24 and the shunt 28. The signal introduced into the track 26 is then able to circulate through this closed loop continuously. In this manner, the receiver 32 is able to receive the signal as it circulates through the closed loop. As long as the rails are intact, the signal introduced into the rails is also intact, and the receiver 32 receives the signal such that it can detect a characteristic of the signal. The characteristic of the signal can be the presence of the signal, the strength of the signal or a signature of signal, that can be detected by digital signal processing techniques, for example. On the basis of one or more of these characteristics, the locomotive 24 can surveys the railway track 26 for possible breaks.

In the case where the receiver 32 no longer receives the signal that is circulating through the railway track 26, it generally means that there is a break in one or both of the rails, thus causing a short in the closed circuit. Alternatively, in the case where the strength of the signal has deteriorated, or the signature of the signal is incorrect, it could also mean that there is a break, or a deterioration of the rails in the portion of the railway track 26 being surveyed. As such, when the receiver 32 fails to receive the track signal, or detects a deterioration in signal strength, or an incorrect signal signature, the locomotive 24 determines that there is a potential break or deterioration in one or both of the rails that it is surveying.

Although FIG. 3 shows only the front end of the locomotive 24, it should be understood that the locomotive 24 may have a similar transmitter 30 and receiver 32 positioned at the rear end of the locomotive 24. In such a non-limiting example embodiment, the locomotive 24 is able to survey both the portion of railway track 26 in front of it and the portion of railway track 26 behind it.

As mentioned above, although the closed loop shown in FIG. 3 is between the front axle 34 of the locomotive 24 and a shunt 28 in the form of a conductive rod, the loop could also be formed between two locomotives 24. For example, in the case where there are no shunts positioned between two locomotives 24 (such as in the case of locomotives 24 b and 24 c shown in FIG. 2) then the closed loop is formed between the rear axle of the front locomotive and the front axle of the rear locomotive.

Shown in FIG. 4 is a representation of the portions of the railway track 26 surveyed by the locomotives 24 a, 24 b and 24 c of FIG. 2. In this non-limiting example, the locomotive 24 a is operative to introduce a signal into the railway track 26 both ahead of it and behind it. As such, the locomotive 24 a is surveying the portion of railway track between its rear axle and the shunt 28 a, as well as the portion of the railway track 26 between its front axle and the shunt 28 b. The locomotive 24 b is also introducing a signal into the railway track 26 both ahead of it and behind it. As such, it is surveying the portion of railway track between its rear axle and the shunt 28 b, and the portion of railway track between its front axle and the rear axle of locomotive 24 c. In the non-limiting example embodiment shown, the locomotive 24 c is only introducing a signal into the railway track ahead of it. As such, locomotive 24 c is only surveying the portion of the railway track 26 between its front axle and the shunt 28 c.

Although in the non-limiting example embodiment shown in FIG. 4, locomotive 24 c is only introducing a signal into the railway track 26 ahead of it, it should be understood that it could also introduce a signal into the railway track behind it. In such as case, both the locomotive 24 b and the locomotive 24 c would be introducing a signal into the portion of railway track positioned between them, such that they are both surveying that portion of the railway track 26. In such a case, it may be beneficial for the two locomotives to introduce signals having two different frequencies into the rail in order to avoid frequency collisions.

As will be described in more detail further on, the monitoring entity 22 is operative for receiving location information from each of the locomotives 24 a, 24 b and 24 c such that the monitoring entity 22 has a complete picture of where each locomotive 24 a, 24 b and 24 c is in relation to the track, and in relation to each other. As such, when the monitoring entity 22 notices that there is a portion of track that is being monitored by two locomotives (such as the portion of track positioned between locomotive 24 b and 24 c) the monitoring entity 22 can issue signals to each of these two locomotives in order to assign to each of the locomotives a specific carrier frequency for the signals that that locomotive transmits into, and receives from, the track 26. Alternatively, the monitoring entity 22 can issue signals to only one of the locomotives, such as locomotive 24 c, for example, in order to instruct that locomotive to stop transmitting a signal into the track behind it. In such a case, the portions of the railway track 26 being surveyed would be as shown in FIG. 4. In the case where the monitoring entity 22 transmits signals to the locomotives 24, the monitoring entity 22 would also include a transmitter.

As such, it should be understood that the manner in which the locomotives 24 survey the railway track 26 can be dependent on the configuration of the tracks, or on the basis of the number of locomotives 24 travelling on the track 26. The decision as to which locomotives perform the surveying operation, and which transmitters are used, can be predetermined, or can be dynamically controlled as the locomotives 24 travel across the railway track 26. For example, in the case where there are many locomotives 24 travelling across the track 26, it may be determined that each locomotive 24 will only transmit and receive track signals from their front ends. Alternatively, it may be determined that only every second locomotive 24 will perform the railway track surveying. In accordance with a non-limiting example embodiment, the co-ordination of the dynamically changing surveying operations will be controlled by the monitoring entity 22, which is in communication with each locomotive 24.

In yet another non-limiting example embodiment, it is possible that one locomotive 24 transmits a signal into the rails, and that another locomotive 24 receives the signal. As such, only one locomotive transmits and only one locomotive receives.

Shown in FIG. 5 is a non-limiting block diagram of the components of a locomotive 24 that perform the functionality of the broken rail detection. As described above, the locomotive 24 includes the rail transmitter 30 and the rail receiver 32. The locomotive 24 further includes a processing unit 40 and a transceiver 42. The processing unit 40 includes a signal generation unit 46 in communication with the transmitter 30, and a signal detection unit 44 in communication with the receiver 32. In the case where the locomotive 24 includes a transmitter 30 and a receiver 32 at both the front and back of the locomotive, the locomotive may include two processing units 40, one for each of the transmitter/receiver pairs.

The transceiver 42 is operative for communicating over a wireless communication link with the monitoring entity 22. It should be appreciated that the transceiver 42 of the locomotive 24 and the receiver 21 of the monitoring entity 22 are operative to communicate over a wireless communication link. In accordance with a non-limiting example embodiment, this wireless communication link is an RF communication link, however, other suitable communication links could also be used without departing from the spirit of the invention. In addition, although FIG. 5 shows the locomotive 24 as having a transceiver 42, the locomotive 24 could instead have included a separate receiver and transmitter for communicating with the monitoring entity 22.

In operation, the signal generation unit 46 is operative for generating a current or voltage signal for being introduced into the rails by the transmitter 30. In the case where the signal being generated is a current (audio) signal, the signal generation unit 46 may include a programmable selectable oscillator, such that the frequency of the signal being introduced into the rails can be selected. It should be understood that the frequency of the signal generated by the signal generation unit 46 may be constant such that it is always the same, or may be selected based on a set of pre-programmed instructions stored in the memory unit 48. Alternatively, the frequency of the signal generated by the signal generation unit may be selected on the basis of a control signal from the monitoring entity 22. As described above, this may occur in the case where the frequency of the signals is selected in order to avoid frequency collisions with signals originating from other locomotives. Alternatively, in the case where the locomotives travelling on the track 26 are able to communicate with one another, and they are surveying the same portion of track, the locomotives can communicate in order to establish different carrier frequencies for their respective signals. Alternatively, in the case where two different signals are travelling in the same portion of railway track 26, the signal signatures can be used to differentiate between the two signals. For example, the locomotives may use a signal sorting techniques, such as signal signature analysis, in order to differentiate the two signals travelling in the track.

As described above, once the transmitter 30 has introduced the signal into the closed loop of the railway tracks 26, the receiver 32 receives this signal (assuming there are no breaks in the rails). The signal detection unit 44, which is in communication with the receiver 32 is operative for detecting from the receiver 32 the presence of the signal circulating in the rails. The signal detection unit 44 is further operative to measure the signal strength to help in determining the rail status. A weak signal may indicate a deterioration of the railway track 26. Likewise, the signal detection unit 44 may also detect the signal signature.

The receiver 32 may be a programmable selectable receiver 32, such that it is able to adjust the frequency of the signals it is receiving. The programmable selectable receiver 32 can select the frequency of signals to be received in the same manner as the frequency of the signals generated by the signal generation unit 46 selects the frequency of signals to be transmitted.

In addition to detecting the presence of the track signal, the processing unit 40 is also operative for detecting the location of the locomotive 24 on the railway track 26 as it travels along. This may be done in a variety of manners, such as those described below.

In a non-limiting example embodiment, the locomotive 24 is operative for determining its location based on track-side positioning devices. For example, positioned along the railway track 26 can be transponders, or some other type of wayside information storage device. The transponders are located at various positions along the railroad track 26 and include coded information that is stored by tuned resonators. In order to read the coded information from these transponders, one or more antennas 50, which utilise a given frequency band and which emit an electromagnetic wave in that frequency band are positioned on the locomotive 24. As such, when the locomotive 24 transporting the one or more antennas 50 passes in the vicinity of a transponder, the antenna emits electromagnetic waves in a frequency band to which the transponder is tuned, such that the antenna's electromagnetic waves power the transponder. This causes the resonator circuit in the transponder to resonate, which results in the transmission of the data stored therein. This data is received by the antenna 50 and is transmitted to the signal detection unit 44 that is coupled to the antenna 50.

In accordance with this example, the locomotive 24 includes a map of the railway track 26 that includes an indication of where the transponders are located on the railway track, as well as their associated coded information. This map can be stored in the memory unit 48. As such, the processing unit 40 is operative to process the coded information received from the antenna 50 in combination with the map, such that it can determine its location on the railroad track 26.

In an alternative non-limiting example embodiment, the locomotive is operative to determine its location on the railroad track 26 based on GPS technology. In this example, the processing unit 40 would be equipped with a GPS receiver such that it can receive GPS co-ordinates from a GPS satellite. These GPS co-ordinates can then be plotted on a corresponding map (which could be stored in the memory 48), such that the processing unit 40 could determine the locomotive's position on the railway track 26.

As shown in FIG. 6, and as described above, the locomotives 24 a, 24 b and 24 c of the system 20 are in communication with the monitoring entity 22, such that information can be transmitted between the locomotives 24 a, 24 b and 24 c and the monitoring entity 22. During normal operation, the locomotives 24 a, 24 b and 24 c, are operative for continually transmitting their location information to the monitoring entity 22 via transceiver 42. In this manner, the monitoring entity 22 is aware of the location of each locomotive 24 a, 24 b and 24 c travelling in its region.

Referring to the flowchart of FIG. 7, the process of surveying a portion of railway track that is performed by one or more of locomotive 24 a, 24 b and 24 c will be described.

At step 60, the receiver 32 receives the signal circulating in the railway track 26 and the signal detection unit 44 monitors a characteristic of this track signal, whether it is the presence of the signal, the strength of the signal, or the signature of the signal. As described above, the track signal can be introduced into the rail by the locomotive 24 that is doing the signal monitoring, by another locomotive 24 or even by the monitoring entity 22.

At step 62, the signal detection unit 44 continuously monitors the characteristic of the track signal. In the case where the characteristic of the track signal being monitored has not changed, the receiver 32 and the signal detection unit 44 continue to monitor the track signal.

In the case where the signal detection unit 44 detects that the characteristic of the signal being received at receiver 32 has changed, whether that is the presence of the signal, the strength of the signal or the signature of the signal, the signal detection unit 44 proceeds to step 64 where it generates a signal indicative of a potentially broken rail. The generated signal can include an indication as to whether it the broken rail was detected in front of the locomotive or behind the locomotive. The signal detection unit 44 then passes this signal to the transceiver 42, such that at step 66, the transceiver 42 transmits the signal indicative of a potential broken rail to the monitoring entity 22.

The signal indicative of a potentially broken rail can include a variety of information. In accordance with a non-limiting example embodiment, the signal indicative of a potential broken rail advises the monitoring entity 22 of the portion of the railway track 26 it was surveying, and thus in which portion of track there could be a broken rail. For the sake of example, it is assumed that locomotive 24 b in FIG. 2 has issued a signal to the monitoring entity 22 indicative of a potential broken rail.

In accordance with this example, the locomotive 24 b includes a map of the railway track 26 over which it is travelling. The map may include the location of the shunts 28 a, 28 b and 28 c on the track, as well as the location of the switches and any other relevant rail information. This map may be stored in the memory unit 48, for example. The map may also be downloaded to the locomotive 24 b prior to its journey, or the map can be transmitted to the locomotive 24 b from the monitoring entity 22. In such as scenario, as the train passes into a region covered by a different monitoring entity 22, it is operative to receive a new map from the new monitoring entity 22.

In accordance with this example, the monitoring entity 22 is operative to transmit to the locomotive 24 b information associated with the railway track on which it is travelling.

For example, the monitoring entity 22 may transmit information to the locomotive 24 b indicative of the location of shunts, the location of other locomotives travelling on the track 26, or the location of other items, such as switches located on the track 26.

Therefore, as the locomotive 24 b travels over the railway track 26, it receives location information from the track-side transponders (or GPS), such that it is able to confirm/determine its position on the map, and also receives information indicative of the position of upcoming shunts and other locomotives 24 from the monitoring entity 22. This information is then stored in the memory unit 48 of the processing unit 40. Based on all this information the locomotive 24 b has a complete picture of the things shunting the track 26 both ahead of it and behind it. As such, the locomotive 24 b can accurately determine the portion of the railroad track 26 that it is surveying, at any point in time.

Keeping with the example of locomotive 24 b, and assuming that the locomotive 24 b is positioned in the location as shown in FIG. 2, based on the information received from the track-side transponders, and the information received from the monitoring entity 22, the locomotive 24 b would know that it is positioned between shunt 28 b and shunt 28 c, and that locomotive 24 c is positioned between it and the shunt 28 c. On the basis of this information, the processing unit 40 would be able to determine that it is surveying the portion of railway track 26 between its rear axle and the shunt 28 b, and the portion of railway track 26 between its front axle and the rear axle of locomotive 24 c. As such, in the case where the locomotive 24 b detects a change in the signal characteristic being monitored, the signal indicative of a potential broken rail that it transmits to the monitoring entity 22 is indicative that there is a potential broken rail in the portion of railway track between its front axle and the rear axle of the locomotive 24 c.

In accordance with a non-limiting example embodiment, the signal indicative of a potential broken rail that is sent from the locomotive 24 b to the monitoring entity 22 may simply be indicative of a change in the characteristic of the track signal being monitored. As mentioned above, this change in characteristic may be the absence of the track signal, a decrease in signal strength or a change in signal signature, among other possibilities. In such a situation, the processing performed to determine the portion of railway track being surveyed by the locomotive 24 b is performed at the monitoring entity 22 instead of at the locomotive 24 b.

In such an example embodiment, the transceiver 42 shown in FIG. 5 may simply be a transmitter, since the locomotive 24 b does not need to receive any railway track information from the monitoring entity 22. Instead, the locomotive 24 b is only aware of its current location information, which is continually sent to the monitoring entity 22, and that is has detected a change in the track signal that is circulating in the railway track 26. The locomotive 24 b is not aware of the positioning of other locomotives, or the positioning of the shunts on the railway track 26. Therefore, the locomotive 24 b is not aware of the portion of the railway track that it is surveying.

In such an example embodiment, upon receipt of the signal indicative of a potential broken rail from the locomotive 24 b, the monitoring entity 22 is operative for processing the location information from locomotive 24 b in combination with the location information of the other locomotives 24 a and 24 c, and the location information associated with the shunts and switches located on the railway track 26. Based on this information, the monitoring entity 22 is operative to determine the portion of railway track 26 that was being surveyed by the locomotive 24 b at the time the locomotive 24 b sent the signal indicative of the potential broken rail.

For the sake of example, it is assumed that the locomotive 24 b sends a signal indicative of a potential broken rail when it is in the position on the railway track shown in FIG. 2. In such a case, the monitoring entity 22 knows the position of locomotive 24 b, and knows that locomotive 24 c is positioned between locomotive 24 b and the shunt 28 b. Based on this information, the monitoring entity 22 can determine that the portion of railway track being surveyed by the locomotive 24 b at the time it sent the signal indicative of the potential broken rail, is the portion of railway track 26 between the front axle of locomotive 24 b, and the rear axle of locomotive 24 c. As such, the monitoring entity 22 is operative for determining the portion of railway track 26 in which there is a broken rail.

Regardless of whether the determination of the portion of railroad track 26 being surveyed by the locomotive 24 b is performed by the locomotive 24 b, or the monitoring entity 22, upon receipt of a signal indicative of a potential break in the rail, the monitoring entity 22 is operative to determine that there is a broken rail in a portion of railway track 26 in its region. More specifically, based on the signals received from all the locomotives 24 a, 24 b and 24 c travelling along the railway track 26, the monitoring entity 22 is operative for determining a complete picture of the condition of the railway track 26. Upon detection of a broken rail within its region, the monitoring entity 22 may forward this information to a central control unit that is in communication with multiple monitoring entities 22, such that the control unit can determine how to proceed. Alternatively, the monitoring entity 22 may issue a signal to advise railway maintenance workers that there is a potential broken rail in a certain portion of the railway track. In this manner, the maintenance workers can go to the specific section of railway track identified and can then find the location of the broken rail, and repair it.

As such, the monitoring entity 22 is operative for detecting broken rails in the region of railway track in large part on the basis of signals received from the locomotives 24 a, 24 b and 24 c. However, as shown in FIG. 6, the monitoring entity 22 may also use conventional detectors 64 for detecting broken rails, in combination with the methods described above. Conventional methods of detecting a broken rail may be used in portions of the railway track that include difficult physical layouts, such as switches, that may cause a locomotive to provide a false broken rail reading. For example, referring to FIG. 2, the monitoring entity 22 may use the traditional broken rail detection techniques to detect broken rails in the portion of railway track 26 between shunt 28 c and 28 d. As described above, a conventional method of broken rail detection involves a transmitter and a receiver that are either connected directly to the monitoring entity 22, or that are connected to wayside equipment that is then in turn connected to the monitoring entity 22.

In a non-limiting example embodiment, as the locomotive 24 c passes the shunt 28 c, the monitoring entity 22 may issue a signal to the locomotive 24 c advising the locomotive not to perform broken rail detection in this region. Alternatively, in the case where the locomotive 24 c does continue to perform broken rail detection in this region, when the monitoring entity 22 receives a signal indicative of a broken rail from the locomotive 24 c, the monitoring entity 22 knows that there is a railway switch within this section that may cause the locomotive 24 c to detect a false broken rail. Once the locomotive 24 c has passed outside of this section, the monitoring entity 22 would use the conventional equipment 64 to determine whether there is in fact a broken rail within the section. In this manner, the processing unit 23 of the monitoring entity 22 may have to filter out false detection readings and combine information received from multiple different sources, i.e., more than one locomotive, or a locomotive in combination with conventional techniques, in order to determine whether there is a broken rail in a portion of its railway track 26.

In addition, while the method of performing broken rail detection using the locomotives works well while there are many locomotives travelling on the railway track 26, in the case where there are no locomotives travelling along the railway track 26, the monitoring entity 22 may choose to perform broken rail detection using a conventional method, which can easily survey large sections of railway track 26 between shunts.

Those skilled in the art should appreciate that in some non-limiting example embodiments of the invention, all or part of the functionality previously described herein with respect to the locomotive 24, and the monitoring entity 22, may be implemented as pre-programmed hardware or firmware elements (e.g., application specific integrated circuits (ASICs), electrically erasable programmable read-only memories (EEPROMs), etc.) or other related components.

In other non-limiting example embodiments of the invention, all or part of the functionality of the locomotives 24, and the monitoring entity 22 may be implemented as software consisting of a series of instructions for execution by a computing unit. The series of instructions could be stored on a medium which is fixed, tangible and readable directly by the computing unit (e.g., removable diskette, CD-ROM, ROM, PROM, EEPROM or fixed disk) or the instructions could be stored remotely but transmittable to the computing unit via a modem or other interface device (e.g., a communications adapter) connected to a network over a transmission medium. The transmission medium may be either a tangible medium (e.g., optical or analog communications lines) or a medium implemented using wireless techniques (e.g., microwave, infrared or other transmission schemes).

As shown in FIG. 5, the processing unit 40 of the locomotive 24 includes a memory 48 connected to both the signal generation unit 46 and the signal detection unit 44 by a communication bus. The memory 48 may include data and program instructions. The processing unit 40 is adapted to process the data and the program instructions in order to implement the method of performing broken rail detection described herein and depicted in the drawings.

Although the present invention has been described in considerable detail with reference to certain non-limiting example embodiments thereof, variations and refinements are possible without departing from the spirit of the invention. Therefore, the scope of the invention should be limited only by the appended claims and their equivalents. 

1-33. (canceled)
 34. A locomotive for travelling on a railway track, comprising: a receiver configured to receive a track signal circulating in the railway track; a processor unit in communication with the receiver, the processor unit configured to: (a) detect a characteristic of the track signal; and (b) generate a signal indicative of a potential broken rail in response to a change in the characteristic of the track signal circulating in the railway track.
 35. The locomotive according to claim 34, wherein the characteristic includes presence of the track signal circulating in the railway track.
 36. The locomotive according to claim 34, wherein the characteristic includes a strength of the track signal circulating in the railway track.
 37. The locomotive according to claim 34, wherein the characteristic includes a signature of the track signal circulating in the railway track.
 38. The locomotive according to claim 34, further comprising a transmitter configured to transmit the track signal into the railway track.
 39. The locomotive according to claim 38, wherein the track signal includes a low frequency signal.
 40. The locomotive according to claim 39, wherein the track signal includes an audio signal.
 41. The locomotive according to claim 38, wherein the processor unit includes a signal generation unit in communication with the transmitter, the signal generation unit configured to select a frequency of the track signal.
 42. The locomotive according to claim 41, wherein the receiver is configured to select a frequency of track signals being detected.
 43. The locomotive according to claim 34, further comprising a wireless transmitter configured to transmit the signal indicative of a potential broken rail to a monitoring entity.
 44. The locomotive according to claim 43, wherein the wireless transmitter is configured to transmit, to the monitoring entity, information indicative of a location of the locomotive.
 45. The locomotive according to claim 43, further comprising a wireless receiver configured to receive signals from the monitoring entity.
 46. The locomotive according to claim 45, wherein the wireless receiver is configured to receive railway track information from the monitoring entity.
 47. The locomotive according to claim 46, wherein the railway track information includes information indicative of at least one of: (a) a location of a shunt on the railway track; (b) a location of another locomotive on the railway track; and (c) a position of a switch on the railway track.
 48. The locomotive according to claim 43, wherein the signal indicative of a potential broken rail includes information associated with a portion of track surveyed by the locomotive.
 49. The locomotive according to claim 45, wherein the wireless transmitter and the wireless receiver are configured to communicate with the monitoring entity over an RF communication link.
 50. A system for performing broken rail detection on a railway track, comprising: at least one locomotive including: a receiver configured to receive a track signal circulating in the railway track; a processor unit in communication with the receiver and configured to: (a) detect a characteristic of the track signal; and (b) generate a signal indicative of a potential broken rail in response to a change in the characteristic of the track signal circulating in the railway track; and a wireless transmitter configured to transmit the signal indicative of a potential broken rail over a wireless communication link; and a monitoring entity including: a receiver configured to receive the signal indicative of a potential broken rail from the locomotive; and a processor unit configured to detect a broken rail at least in part in accordance with the signal indicative of a potential broken rail from the locomotive.
 51. The system according to claim 50, wherein the characteristic includes presence of the track signal circulating in the railway track.
 52. The system according to claim 50, wherein the characteristic includes a strength of the track signal circulating in the railway track.
 53. The system according to claim 50, wherein the characteristic includes a signature of the track signal circulating in the railway track.
 54. The system according to claim 50, wherein the locomotive includes a transmitter configured to transmit the track signal into the railway track.
 55. The system according to claim 50, wherein the wireless transmitter is further configured to transmit a signal indicative of a location of the locomotive to the monitoring entity.
 56. The system according to claim 50, wherein the locomotive includes a wireless receiver configured to receive signals from the monitoring entity.
 57. The system according to claim 56, wherein the wireless receiver is configured to receive railway track information from the monitoring entity.
 58. The system according to claim 57, wherein the railway track information includes information indicative of at least one of: (a) a location of a shunt on the railway track; (b) a location of another locomotive on the railway track; and (c) a position of a switch on the railway track.
 59. The system according to claim 50, wherein the signal indicative of a potential broken rail includes information associated with a portion of track surveyed by the locomotive.
 60. The system according to claim 50, wherein the monitoring entity is configured to initiate an action upon detection of a broken rail.
 61. The system according to claim 60, wherein the action includes sending a repair team to repair the broken rail.
 62. A monitoring entity for performing broken rail detection, comprising: a wireless receiver configured to receive a signal, indicative of a potential broken rail, from at least one locomotive; a processor unit configured to detect a broken rail at least in part in accordance with the signal from the locomotive.
 63. The monitoring entity according to claim 62, wherein the signal indicative of a potential broken rail includes information indicative of a portion of track surveyed by the locomotive.
 64. The monitoring entity according to claim 62, further comprising a wireless transmitter configured to transmit railway track information to the locomotive.
 65. The monitoring entity according to claim 64, wherein the railway track information includes information indicative of at least one of: (a) a location of a shunt on the railway track; (b) a location of a locomotive on the railway track; and (c) a position of a switch on the railway track.
 66. A system for performing broken rail detection, comprising: a receiver mountable onboard a locomotive that travels on a railway track, the receiver configured to receive a track signal circulating in the railway track; and a processor device configured to communicate with the receiver, the processor device configured to: (a) detect a characteristic of the track signal; and (b) generate a signal indicative of a potential broken rail in response to a change in the characteristic of the track signal circulating in the railway track. 